Degree
Doctor of Philosophy (PhD)
Department
Chemical Engineering
Document Type
Dissertation
Abstract
This dissertation introduces computational tools to accurately simulate electrocatalytic processes in a realistic electrochemical environment while solving limitations of existing implicit solvation models in plane wave density functional theory. It describes the development and implementation of an implicit electrolyte model in the Vienna Ab initio Simulation Package (VASP) that includes nonlinear dielectric and ionic responses as well as a nonlocal definition of the cavities. The implementation into the existing VASPsol code is numerically efficient and exhibits robust convergence, requiring computational effort only slightly higher than the original linear polarizable continuum model. The nonlinear + nonlocal model is able to reproduce the characteristic “double hump” shape observed experimentally for the differential capacitance of an electrified metal interface while preventing “leakage” of the electrolyte into regions of space too small to contain a single water molecule or solvated ion. The model also gives a reasonable prediction of molecular solvation free energies as well as the self-ionization free energy of water and the absolute electron chemical potential of the standard hydrogen electrode. All of this, combined with the additional ability to run constant potential density functional theory calculations, should enable the routine computation of activation barriers for electrocatalytic processes. Additionally, a hybrid solvation methodology is introduced which enhances accuracy in predicting pKa values and free energies by incorporating explicit water molecules, aligning closely with experimental data. The research further applies these models to analyze the behavior of the Pt(111) surface under varying pH and potentials, constructing a Pourbaix diagram that elucidates the stability of surface states.
Date
4-2-2025
Recommended Citation
Islam, S M Rezwanul, "DEVELOPMENT AND APPLICATION OF A NONLINEAR/NONLOCAL IMPLICIT ELECTROLYTE MODEL TO STUDY ELECTROCHEMICAL SYSTEMS USING PLANE WAVE DENSITY FUNCTIONAL THEORY" (2025). LSU Doctoral Dissertations. 6747.
https://repository.lsu.edu/gradschool_dissertations/6747
Committee Chair
Plaisance, Craig